If you need assistance, please send an email to forum at 4hv dot org. To ensure your email is not marked as spam, please include the phrase "4hv help" in the subject line. You can also find assistance via IRC, at irc.shadowworld.net, room #hvcomm.
Support 4hv.org!
Donate:
4hv.org is hosted on a dedicated server. Unfortunately, this server costs and we rely on the help of site members to keep 4hv.org running. Please consider donating. We will place your name on the thanks list and you'll be helping to keep 4hv.org alive and free for everyone. Members whose names appear in red bold have donated recently. Green bold denotes those who have recently donated to keep the server carbon neutral.
Special Thanks To:
Aaron Holmes
Aaron Wheeler
Adam Horden
Alan Scrimgeour
Andre
Andrew Haynes
Anonymous000
asabase
Austin Weil
barney
Barry
Bert Hickman
Bill Kukowski
Blitzorn
Brandon Paradelas
Bruce Bowling
BubeeMike
Byong Park
Cesiumsponge
Chris F.
Chris Hooper
Corey Worthington
Derek Woodroffe
Dalus
Dan Strother
Daniel Davis
Daniel Uhrenholt
datasheetarchive
Dave Billington
Dave Marshall
David F.
Dennis Rogers
drelectrix
Dr. John Gudenas
Dr. Spark
E.TexasTesla
eastvoltresearch
Eirik Taylor
Erik Dyakov
Erlend^SE
Finn Hammer
Firebug24k
GalliumMan
Gary Peterson
George Slade
GhostNull
Gordon Mcknight
Graham Armitage
Grant
GreySoul
Henry H
IamSmooth
In memory of Leo Powning
Jacob Cash
James Howells
James Pawson
Jeff Greenfield
Jeff Thomas
Jesse Frost
Jim Mitchell
jlr134
Joe Mastroianni
John Forcina
John Oberg
John Willcutt
Jon Newcomb
klugesmith
Leslie Wright
Lutz Hoffman
Mads Barnkob
Martin King
Mats Karlsson
Matt Gibson
Matthew Guidry
mbd
Michael D'Angelo
Mikkel
mileswaldron
mister_rf
Neil Foster
Nick de Smith
Nick Soroka
nicklenorp
Nik
Norman Stanley
Patrick Coleman
Paul Brodie
Paul Jordan
Paul Montgomery
Ped
Peter Krogen
Peter Terren
PhilGood
Richard Feldman
Robert Bush
Royce Bailey
Scott Fusare
Scott Newman
smiffy
Stella
Steven Busic
Steve Conner
Steve Jones
Steve Ward
Sulaiman
Thomas Coyle
Thomas A. Wallace
Thomas W
Timo
Torch
Ulf Jonsson
vasil
Vaxian
vladi mazzilli
wastehl
Weston
William Kim
William N.
William Stehl
Wesley Venis
The aforementioned have contributed financially to the continuing triumph of 4hv.org. They are deserving of my most heartfelt thanks.
Registered Member #54503
Joined: Sun Feb 22 2015, 10:35PM
Location: New Zealand
Posts: 288
Ive just ordered my CDE 942 series caps, 40 of them (5 in series x 8 in parallel) this will give me a bank rated at 10KV which should be sufficient if i pushed my coil up to 1000APK.
Anyway, ive been browsing alibaba, and i know these are chinese, but for the price, they should be worthwhile testing for tesla coil use, since the manufacturer claims they are suitable.
Sometimes the stuff out of china is not always that bad, IDK, but im interested to try them, these are rated at 60A each!
There are many other types listed there also, im interested if anyone has experimented with chinese caps.
Registered Member #1403
Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968
nzoomed wrote ...
Ive just ordered my CDE 942 series caps, 40 of them (5 in series x 8 in parallel) this will give me a bank rated at 10KV which should be sufficient if i pushed my coil up to 1000APK.
Anyway, ive been browsing alibaba, and i know these are chinese, but for the price, they should be worthwhile testing for tesla coil use, since the manufacturer claims they are suitable.
Sometimes the stuff out of china is not always that bad, IDK, but im interested to try them, these are rated at 60A each!
There are many other types listed there also, im interested if anyone has experimented with chinese caps.
Your MMC plan sounds fine for 1000A.
About the Chinese capacitors... Package Type: Surface Mount
Their datasheet seems to be specified for 1kHz/10kHz, I would like to see atleast some 100kHz figures. and
They do specify Dissipation factor: Geasured at 1000±20 Hz AND 25±5℃. When Cr≤1.0µF， 4×10-4； When Cr>1.0µF， 6×10-4, the characteristics of polypropylene is rather linear, but only up until 80kHz, then it starts going up.
A proper field test is surely needed but on the other hand, the pricing is just around where you can find proven surplus caps.
Registered Member #54503
Joined: Sun Feb 22 2015, 10:35PM
Location: New Zealand
Posts: 288
Hydron wrote ...
Big plus with the chinese is shipping is normally reasonable to places US sellers are too lazy or charge too much to ship to (e.g. NZ).
Could be an interesting option for mid sized coils, (~1kA peak), where a single series string might work okay for a rather low total price.
Aliexpress is probably easier to deal with if anyone wants to give it a go!
Yes i agree, i didnt see those particular caps on aliexpress, but there is alot to choose from. Would be great to see some reviews on them, shipping from china is so cheap its not funny.
I need a couple of aerovox snubbers and the shipping is going to cost me 3 times as much to get them here to New Zealand!
There is also tons of cheap variacs on alibaba, (not all chinese, some are from india)
I know most chinese variacs are crap, but if you buy a larger one than what you plan to use, you might get away with it.
Registered Member #54503
Joined: Sun Feb 22 2015, 10:35PM
Location: New Zealand
Posts: 288
Hazmatt_(The Underdog) wrote ...
For a few dollars more each, you could buy capacitors that will not burn up, EVER.
Anything with a high uF value in that form factor is going to be a rolled film capacitor, which will eventually fail.
That's just my opinion though.
Those capacitors in your link are far too low for tesla coil use, i would need tons of them to build a decent MMC around 0.25uf, in fact even if i had the money, i wouldnt fit that many caps on my coil.
Interestingly, the eurofarad doorknobs are rolled film also and are rated at only 2KV each, so lets assume these chinese caps only realistically can rate up to 2KV and not the 4KV they claim, then you might get somewhere with them, who knows, they might work better than you think.
This site is powered by e107, which is released under the GNU GPL License. All work on this site, except where otherwise noted, is licensed under a Creative Commons Attribution-ShareAlike 2.5 License. By submitting any information to this site, you agree that anything submitted will be so licensed. Please read our Disclaimer and Policies page for information on your rights and responsibilities regarding this site.
TDK Ceramic "Doorknob" Capacitors For a Tesla Coil
